Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant’s cancellation of claims 3, 12, and 18-20, as well as the addition of claims 21-24, is acknowledged.
Applicant’s arguments, see pages 8-9, filed 16 April 2026, with respect to the rejection of claims 2 and 11 under 35 U.S.C. 112(b) have been fully considered and are persuasive. The rejection of claims 2 and 11 under 35 U.S.C. 112(b) has been withdrawn.
Applicant has amended instant claims 2 and 11 to state the transfer pattern comprises a line and space having a half pitch of 16 nm or less. The amendment to claims 2 and 11 has overcome the rejection made under 35 U.S.C. 112(b) and therefore the rejection of claims 2 and 11 under 35 U.S.C. 112(b) has been withdrawn.
Applicant’s arguments, see pages 9-14, filed 16 April 2026, with respect to the rejection(s) of claim(s) 1 under 35 U.S.C. 102(a)(1) have been fully considered but they are not persuasive.
Applicant has amended instant claim 1 to recite that the absorber film comprises a material having a refractive index between 0.86 and 0.95 and an extinction coefficient between 0.015 and 0.059 with respect to EUV light having a wavelength of 13.5 nm. Claim 1 has further been amended to recite that the absorber film has a thickness of 50 nm or less. Applicant argues that the previously cited prior art (KR ‘943) discloses an absorber film comprising platinum (Pt), which has an extinction coefficient of 0.0600, and only suggests increasing the extinction coefficient by including an additional metal material with the platinum. Therefore, Applicant argues, KR ‘943 does not disclose the absorber film of instant claim 1, as amended, and actually teaches away from the invention of instant claim 1. However, the Examiner draws attention to Example 3 of the instant application’s specification (see paragraph 0163-0167 of the instant application’s specification). In Example 3, a 40 nm thick absorption layer formed of platinum (Pt) is utilized. The Pt film is reported to have a refractive index of 0.889 and an extinction coefficient of 0.059 with respect to EUV light having a wavelength of 13.5 nm. Whilst these numbers differ from what is reported in paragraph 0086 of the instant application’s specification (as well as KR ‘943), the Applicant’s own admission is that platinum films have refractive index and extinction coefficient values that fall within the ranges recited by instant claim 1. The value of the normalized evaluation function for this example was 1.02. Furthermore, KR ‘943 discloses that the absorbing film may combine the platinum with other metals, such as ruthenium and iridium (KR ‘943, paragraph 0045 of the English translation). Both ruthenium and iridium, by the Applicant’s own admission (per Fig. 11 of the instant application), have a refractive index and extinction coefficient within the claimed range, and also yield an absorber film having a normalized evaluation function of 1.015 or more (refer to paragraph 0139 of the instant application’s specification). Therefore, not only does the Pt film of KR ‘943 satisfy the requirements of instant claim 1, but the combination of Pt with an additional metal can satisfy the requirements of instant claim 1. Accordingly, Applicant’s arguments are not found to be persuasive and therefore the previous rejection is not withdrawn.
Applicant further argues that KR ‘943 does not teach the evaluation function recited by instant claim 1. The Examiner notes that the instant application is silent in regards to the exact methodology utilized to create the evaluation function. Paragraphs 0041-0044 of the instant application’s specification describe the evaluation function as a product of a NILS and a threshold of light intensity for exposure of a predetermined resist to light, and further describes how normalization is performed with respect to a reference absorber film. However, the exact parameters and values input to achieve the evaluation function are not disclosed by the Applicant. The Examiner refers to Fig. 3-11 of the instant application’s specification to evaluate the prior art for satisfying the values of the normalized evaluation function. Furthermore, the instant application’s independent claims are directed towards products (e.g. reflective mask blank and reflective mask). The prior art is not required to disclose, teach, or suggest the claimed evaluation function to anticipate or render obvious the claimed invention, but merely needs to disclose, teach, or suggest each of the structural features of the claimed invention. In other words, a prior art reference that discloses a reflective mask blank and/or reflective mask that is substantially identical to the claimed invention, but is silent in regards to the evaluation function, would still be considered to anticipate the claimed invention due to having all the structural features recited by the claim. Refer to MPEP 2112.01. Applicant’s arguments in this regard are therefore not considered persuasive, as a prior art reference that discloses the structural features of the claimed invention would be expected to satisfy the minimum value of the normalized evaluation function, absent of evidence to the contrary.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim(s) 1-2, 8-9, 11, and 17 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by KR 101772943 B1 (hereby referred to as KR ‘943).
The Examiner notes that all forthcoming references to paragraph numbers, unless otherwise stated, are made in reference to the provided English machine translation of the KR ‘943 specification.
Regarding Claims 1 and 9, KR ‘943 discloses a mask blank for extreme ultraviolet (EUV) lithography and a photomask using the same. The mask blank is shown in Fig. 3 of the original KR ‘943 publication, wherein the mask blank comprises a transparent substrate (202), a multilayer reflective film (204) disposed on the transparent substrate, an absorbing film (212), and optionally a capping film (206) provided between the multilayer reflective film and the absorbing film (KR ‘943, paragraph 0032). The absorption film is composed of a material having a high extinction coefficient for the exposure light (KR ‘943, paragraph 0042). The absorption film essentially includes platinum (Pt) and is formed by including at least one metal material selected from the group of nickel (Ni), tantalum (Ta), zinc (Zn), ruthenium (Ru), rhodium (Rh), silver (Ag), indium (In), osmium (Os), iridium (Ir), and gold (Au), or is formed by further including at least one element selected from the group of oxygen (O), nitrogen (N), carbon (C), boron (B), and hydrogen (H) in addition to the at least one metal material (KR ‘943, paragraph 0043). KR ‘943 further discloses that the absorption film has a thickness of 30 nm to 70 nm (KR ‘943, paragraph 0052). Notably, Example 3 of the instant application’s specification (see paragraph 0163-0167 of the instant application’s specification) describes a 40 nm thick absorption layer formed of platinum (Pt), wherein the Pt film is reported to have a refractive index of 0.889 and an extinction coefficient of 0.059 with respect to EUV light having a wavelength of 13.5 nm. Whilst these numbers differ from what is reported in paragraph 0086 of the instant application’s specification (as well as KR ‘943), the Applicant’s own admission is that platinum films have refractive index and extinction coefficient values that fall within the ranges recited by instant claims 1 and 9. The value of the normalized evaluation function for this example was 1.02. KR ‘943 does not disclose a normalized evaluation function value, as recited by instant claims 1 and 9. However, the instant application’s specification states that when the material of the absorber film has a refractive index in the range of 0.86 to 0.95 and an extinction coefficient in the range of 0.015 and 0.065, a material having a value of the normalized evaluation function of the absorber film of 1.015 or more can easily be obtained (see paragraph 0079 of the instant application’s specification). Furthermore, the instant application’s specification states that simple substances such as Pt have a value of the normalized evaluation function of 1.015 or more (see paragraph 0080 of the instant application’s specification). Thus, whilst KR ‘943 is silent in regards to the normalized evaluation function, the Pt absorber layer disclosed by KR ‘943, by the Applicant’s own admission, satisfies the criteria of instant claims 1 and 9. The described mask blank is used to produce a patterned photomask (KR ‘943, paragraph 0026).
Regarding Claims 2 and 11, KR ‘943 discloses that the mask blank can implement a fine pattern of 14 nm or less, particularly 10 nm or less, by using 13.5 nm EUV light as the exposure light (KR ‘943, paragraph 0001 and 0052). The absorption pattern is a line and space pattern, as shown by Fig. 2a of KR ‘943.
Regarding Claims 8 and 17, KR ‘943 discloses that a capping layer may be disposed between the reflective multilayer film and the absorber film (KR ‘943, paragraph 0032 and 0037). The capping film may be composed of ruthenium or a ruthenium compound (KR ‘943, paragraph 0038).
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 4-7 and 13-16 are rejected under 35 U.S.C. 103 as being unpatentable over KR 101772943 B1 (hereby referred to as KR ‘943).
Regarding Claims 4-7 and 13-16, KR ‘943 discloses an absorber film comprising platinum (Pt) that may further include additional metal species, such as silver (Ag), gold (Au), iridium (Ir), rhodium (Rh), and ruthenium (Ru) (KR ‘943, paragraph 0043). Both ruthenium and iridium, by the Applicant’s own admission (per Fig. 11 of the instant application), have a refractive index and extinction coefficient within the claimed range, and also yield an absorber film having a normalized evaluation function of 1.015 or more (refer to paragraph 0139 of the instant application’s specification). The ratio of the metal elements compared to platinum may be between 95:5 to 5:95 (based on atomic%) (KR ‘943, paragraph 0045). In addition, light elements such as oxygen (O), nitrogen (N), boron (B), hydrogen (H) and carbon (C) may be included in the absorber film (KR ‘943, paragraph 0043).
It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to produce an absorber layer comprising platinum in addition to one or more of the elemental species recited by instant claims 4-7 and 13-16, as suggested by KR ‘943, because the inclusion of the additional species, such as iridium, ruthenium, and/or gold, allows the thickness of the absorber film to be reduced (KR ‘943, paragraph 0045). As the ratio of the metallic species can be within a broad range (see KR ‘943, paragraph 0045), one having ordinary skill in the art would be motivated to routinely optimize the metal alloy content to achieve a desired optical property, such as extinction coefficient, as well as a desired absorber layer thickness. See MPEP 2144.05 II.
Claim(s) 10 is rejected under 35 U.S.C. 103 as being unpatentable over KR 101772943 B1 (hereby referred to as KR ‘943) in view of US 20040196579 A1 (hereby referred to as Shoki).
Regarding Claim 10, KR ‘943 discloses a photomask obtained from the mask blank according to instant claim 9, as discussed above. However, KR ‘943 is silent in regards to a method of manufacturing a semiconductor device using the photomask.
Shoki teaches a method of producing a reflective mask and a method of producing a semiconductor device. The mask comprises a reflective multilayer film, a buffer layer, and an absorber layer successively formed on a substrate (Shoki, paragraph 0042 and Fig. 1A). This is analogous to the structure described by KR ‘943 (in the embodiment wherein a capping layer is disposed between the multilayer reflective film and the absorber film). Shoki further teaches a method of transferring a pattern by EUV light to a semiconductor substrate (Shoki, paragraph 0103). The method involves setting the reflective mask in a pattern transfer apparatus which comprises an EUV wavelength exposure light source (Shoki, paragraph 0104). The exposure light exposes a transfer pattern onto a resist layer formed on a semiconductor silicon wafer (Shoki, paragraph 0106).
KR ‘943 and Shoki are analogous art because both references pertain to reflective mask blanks and reflective photomasks. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to use the reflective mask disclosed by KR ‘943 as the transfer mask in the method of manufacturing a semiconductor device taught by Shoki because the photomask disclosed by KR ‘943 can utilize thinner absorber layers, which reduces the shadow effect (KR ‘943, paragraph 0044), thereby allowing for better pattern transfer (KR ‘943, paragraph 0007) and enabling finer pattern sizes (KR ‘943, paragraph 0008-0011 and 0052).
Claim(s) 21 and 23 are rejected under 35 U.S.C. 103 as being unpatentable over KR 101772943 B1 (hereby referred to as KR ‘943) in view of US 20210389662 A1 (hereby referred to as Seo).
The Examiner notes that Seo claims priority to Korean Application 10-2020-0073145, which gives Seo an effective filing date of 16 June 2020 and therefore Seo qualifies as prior art under 35 U.S.C. 102(a)(2).
Regarding Claims 21 and 23, KR ‘943 discloses a reflective mask blank and a reflective mask according to instant claims 1 and 9, as explained above. However, KR ‘943 is silent in regards to the absorber film acting as a phase shift film.
Seo teaches a phase shift mask for extreme ultraviolet (EUV) lithography. The phase shift mask comprises a substrate, a reflective layer, a capping layer, a buffer pattern, and an absorber pattern (Seo, paragraph 0033). The structure of Seo’s mask is analogous to the mask blank and mask of the instant application. Seo teaches that the absorber pattern may be a chromium-based compound (Seo, paragraph 0042). Chromium is a material that satisfies the requirements of claims 1 and 9, as evidenced by Fig. 11 of the instant application’s specification. The absorber pattern may be considered a phase shift pattern (Seo, paragraph 0042).
KR ‘943 and Seo are analogous art because both references pertain to reflective masks. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to make the absorber act as a phase shift film, as taught by Seo, in the mask blank and mask disclosed by KR ‘943 because using a phase shifting absorber can increase throughput in patterning and improve patterning qualities such as line edge roughness and critical dimension uniformity (Seo, paragraph 0062).
Claim(s) 22 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over KR 101772943 B1 (hereby referred to as KR ‘943) in view of US 20190146331 A1 (hereby referred to as Lin).
Regarding Claims 22 and 24, KR ‘943 discloses a reflective mask blank and a reflective mask according to instant claims 1 and 9, as explained above. However, KR ‘943 is silent in regards to a buffer layer in contact with the multilayer reflective film.
Lin teaches a reflection extreme ultraviolet (EUV) mask. The mask blank comprises a substrate having a reflective multilayer formed over the substrate, a capping layer over the reflective multilayer, and an absorption layer formed over the capping layer (Lin, paragraph 0017-0021). The capping layer may be formed of ruthenium-based or chromium-based materials (Lin, paragraph 0020). The thickness of the capping layer is 0.5 nm to 10 nm (Lin, paragraph 0020). The capping layer of Lin is thus analogous to the buffer layer described by instant claims 22 and 24.
KR ‘943 and Lin are analogous art because both references pertain to reflective masks. It would have been obvious to one having ordinary skill in the art before the filing date of the instant application to include a chromium-based buffer layer between the reflective multilayer and the absorber layer, as taught by Lin, in the mask blank and mask disclosed by KR ‘943 because such a layer protects the reflective multilayer from damage and/or oxidation whilst being transparent to EUV light (Lin, paragraph 0020). Such a layer may also act as an etching stop layer in a patterning process of the absorption layer (Lin, paragraph 0020).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAYSON D COSGROVE whose telephone number is (571)272-2153. The examiner can normally be reached Monday-Friday 10:00-18:00.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Jonathan Johnson can be reached at 571-272-1177. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/JAYSON D COSGROVE/Examiner, Art Unit 1737
/JONATHAN JOHNSON/Supervisory Patent Examiner, Art Unit 1734
Prosecution Insights